THC-CBD sleep study shows altered brain rhythms and delayed dreaming phase

In a small, blinded crossover trial of twenty adults with insomnia, a single oral dose of 10 mg THC plus 200 mg CBD shortened total sleep by about 25 minutes and cut REM sleep by roughly 34 minutes, while delaying REM onset by more than an hour. High-density EEG revealed calmer activity in lighter sleep stages but reduced slow-wave activity in deep sleep and increased fast rhythms in posterior regions during REM, indicating more nocturnal arousal and shallower sleep. Next-day cognitive tests were largely unchanged, though participants reported mild sleepiness. The study’s limitations—small sample size and one-night exposure—call for longer-term research on safety and tolerability of medicinal cannabis for sleep.